Gear Shaping Head Linear Motor Ram Backlash Reduction

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Solution Overview

Problem

Contemporary gear shaping machines require multiple axes of control and suffer from backlash and interference issues due to static motor placement and continuous rotary motion, leading to inefficiencies and inaccuracies in cutting processes.

Innovation Solution

A cutting machine utilizing a linear motor to reciprocate a ram along a single axis, eliminating the need for additional lead guides and incorporating a timed stepped rotary feed to reduce or eliminate rub during the cutting process, allowing for precise control of stroke position, speed, and length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional rotary motor and crankshaft linkage are used for stroke drive, then linear reciprocation of the spindle is achieved, but backlash is inherently present and additional motors and control axes are required

Engineering Contradiction:
Improvestroke position controlVSAvoidbacklash
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces the conventional mechanical crankshaft linkage system with a linear motor system. The linear motor directly generates linear motion without mechanical linkages, eliminating backlash inherent in crankshaft mechanisms. The control system manages stroke position, speed, and length through electronic control of the linear motor, removing the need for additional mechanical motors and control axes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts and removes the crankshaft and linkage components from the stroke drive system. By taking out these mechanical elements, the system eliminates the source of backlash and simplifies the control architecture, requiring only a single axis of control for the linear motor.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If a lead guide is used to maintain spindle straightness during reciprocation, then spindle alignment is improved, but device complexity increases

Engineering Contradiction:
Improvespindle straightnessVSAvoidlead guide
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent removes the lead guide component from the system. Instead of using a lead guide to maintain spindle straightness, the linear motor itself provides precise linear motion control, and the spindle is guided through the inherent rigidity of its mounting and the precision of the linear motor's motion control, thereby reducing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical lead guide system is replaced with an electronically controlled linear motor system. The linear motor provides direct linear motion with high precision, eliminating the need for mechanical guidance elements like lead guides, thus reducing overall device complexity while maintaining or improving precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the spindle continuously rotates during reciprocation, then gear meshing is achieved, but interference with the workpiece trailing flank occurs during return stroke

Engineering Contradiction:
Improvecontinuous cuttingVSAvoidrub
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies dynamic control to the spindle rotation, transitioning from continuous rotation to stepped rotation. During the return stroke, the spindle rotation is paused or stepped, preventing the cutting gear from interfering with the workpiece trailing flank. This dynamic adjustment of rotational motion eliminates rub while maintaining productivity during the cutting stroke.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention implements periodic rotation of the spindle synchronized with the reciprocating motion. The spindle rotates during the cutting stroke and pauses during the return stroke, creating a periodic motion pattern that prevents continuous contact and eliminates rub between the cutting gear and workpiece trailing flank.

Inventive Principle:
Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution simplifies control by managing machining parameters over a single axis, reduces backlash, and minimizes interference, enhancing the precision and efficiency of the gear shaping process.

Implementation Method 1

A cutting machine utilizes a linear motor to reciprocate a ram along a single axis

Methodology Applied
Scientific EffectLinear motor: Linear Motor

Data Source

PatentEP2560781B1Cutting machine for gears, splines & other shapes
Publication Date: 2018.11.28 BOURN & KOCH INC
  • EP2560781B1 patent drawingFigure 1
  • EP2560781B1 patent drawingFigure 2
  • EP2560781B1 patent drawingFigure 3

AI summary

A cutting machine for gear shaping or the like is provided. The cutting machine includes a gear shaping head. The gear shaping head has a ram that is guided by and reciprocates along a linear guide mounted between a saddle of the gear shaping head and the ram. At least one linear motor reciprocates the ram along a stroke axis relative to the saddle. The ram also carries a rotary drive and a spindle that reciprocate in unison with the ram. The rotary drive directly drives the spindle to journal the spindle through incremental angular positions during gear shaping.